Motion picture projector and control system therefor



Oct. 28, 1941. H. 5. CUNNINGHAM ETAL 2,260,299

MOTION PICTURE PRGJECTOR AND CONTROL SYSTEM THEREFOR Filed Jan. 30, 1959 4 Sheets-Sheet 1 Pnwscrae fifumv 6 CUNN/NGHAM, JOHN A1. T/WLLSO/V,

1941 H rs. CUNNINGHAM ETAL 2,260,299

MOTIUN PICTURE PROJECTOR AND CONTROL SYSTEM THEREFOR Filed Jan. 30, 1959 4 Sheets-Sheet 2 G'- Cb/v/v/Ns/MM, A1. PWLLSON, WW

- Oct. 28, 1941.

H. G. CUNNINGHAM ETAL v 2,260,299 MOTION PICTURE PROJECTOR AND CONTROL SYSTEM THEREFOR Filed Jan. 50, 1959 4 Sheets-Sheet 3 CONOENS'ER Oct. 28, 1941. H, cuNNlNGHAM ET AL 2,260,299

7 MOTION PICTURE PROJECTOR AND CONTROL SYSTEM THEREFOR Filed Jan. 30, 1939 4 Sheets-Sheet 4 w; wwzzw Patented Qct, 28, 1941 MOTION PICTURE PROJECTOR AND CON- Harry G. Cunningham,

Willson, Burbank, Calit, Keith Orpheum Corporation,

Maryland SYSTEM THEREFOR Hollywood, and John M.

assignors to Radio a corporation of Application January 30, 1939, Serial No. 253,612

14 Claims.

This invention relates to motion picture apparains and particularly to a motion picture projector adapted to project upon a translucent screen a motion picture background scene for combination with a foreground action, both of which are simultaneously photographed from the other side of the screen.

In the production of motion pictures, process shots are well known, such shots consisting of a previously photographed scene which is projecte'd on a screen located behind the actors. It is also well known that rehearsals are made before the final take of any particular scene, and, since such process shots are no exception, the background picture must be repeatedly projected during the rehearsals and also for the final take.

The present invention, therefore, is directed to a background motion picture film projector wherein the projector is made extremely flexible with respect to operation. That is, the film may be run forward or backward at'will and at various speeds. This is desirable, since only certain portions of a background film might be rehearsed several times and the present invention permits returning the projector to the beginning of the particular scene quickly without necessitating the dismounting of the film reels and rewinding as was formerly required. According to the invention disclosed hereinafter, the operator of the projector need only manipulate a single switch control handle to quickly bring any point in the reel to the projection gate, thus saving time and money in the production of process shots.

It is also well known that in the taking of this type of shot, the camera and projector shutters must be synchronized so that they are open at the same periods. provides means for aligning the respective shutters, but means whereby the film b ing projected may be advanced backward and forward between projections without disturbing the original synchronized adjustment. h

Theprincipal object ofthe invention, therefore, is to facilitate the projection ofmotion picture film. I

Another object of the invention is to facilitate the control of a motion picture projector.

A further object of the invention is to control the direction and speed of film travel through a motion picture projector from a single control eh nent.

A further object of the invention is to provide a motion picture projector which projects a picture in synchronism with a motion picture cam- The present invention not only ments of the switch taken along era and a mechanism which may advance or reverse the film in the projector at will.

A further object of the invention is to disconnect a motion picture projector from its synchronous driving motor, control the speed and direction of the projector while disconnectedand connect the projector back in synchronous position.

Although the novel features which are believed to be characteristic of this invention are pointed out with particularity in the claims appended herewith, the manner of its organization'and the mode of its operation will be better understood by referring to the following description read in conjunction with the accompanying. drawings forming a part thereof, in which Figure l is a diagrammatic drawing of a motion picture process shot employing the projector of the invention; I

Figure 2 is an elevational view partially in cross-section of the projector embodying the invention taken along the line 2-2 of Figure 1;

Figure 3 is a cross-sectional'view of the clutch and synchronizing mechanism'of the projector;

Figure 4 isa detail plan view of Figure 3 taken along the line 4-4 of Figure 3; Figure 5 is a detail of the clutch taken along the line 5-5 of Figure 3;

Figure 6 is a sectional view on line 6-6 of Figure 7,.showing the control switch of the invention;

Figure '7 is a cross-sectional view of the switch taken along the lineL-l of Figure 6;

Figure 8 is -a detail view of the contact seathe line 8-8 of Figure 7; and

Figure 9 is a diagrammatic view of the control switchand circuit of the invention.

Referring now to Fig. 1, the invention is em bodied in a projector 5 portably mounted for movement about a stage or set. The projector-5 is shown positioned behind a translucent screen 8, in front of which is shown an actor I. backgroundscene on the screen 6 'and the actor 1 i photographed by a camera 8 positioned in front of the screen. The projector 5, as stated above, is adapted to project a motion picture film on the screen 6 during the photographing of the picture by the camera 8, the respective shutters of the projector and camera opening and closing in synchronism, since the respective motors are electrically interlocked.

' Referring now to the specific mechanism for controlling the film advancement through the projector, reference is made to the remaining The figures, in which like elements are identified by the same numerals. The projector as shown in Fig. 2 comprises a base III which supports the synchronous main driving motor I I for advancing the film during projection. The motor is connected to the usual intermittent; motion and film reels through a frame adjusting assembly I3 and a clutch I4, power being transmitted to a film reel I! through a drive shaft I 8 and to a film reel I8 through a similar shaft within the housing 28. The intermittent film motion may be of the standard type within a housing 23, projection of the film being made through a lens tube 22, a door mounted on hinges 24 being provided to obtain access to the interior of the projector for threading the film therethrough.

For purposes of this invention, as explained hereinafter, a second motor I is employed, this motor either advancing or reversing the film through the projector 5. Thus, the film reels. I! and 49 function as either takeup or supply reels according to the direction of film travel through the projector. To permit the reels to function in this manner, an overrunning clutch mechanism in housing 28 is provided for reel I9 and a similar mechanism shown in cross-section is provided for reel I'I.

Referring now to this overrun clutch mechanism shown in cross-section, the shaft I8 is geared to a quill 30 which drives a cupped disc 3| having pawls 32 diametrically positioned thereon. When the reel II is to actas a takeup reel, the shaft I8 rotates the disc 3| in a direction so that the pawls 32 positively engage a friction disc member 34, which contacts, through friction discs 35, a plate 36 which is fixed to a shaft 38 rotatable within quill 36 and to which is attached the reel ll. Thus the reel II is positively driven as a takeup reel, variations in film reel diameter being compensated for by the slippage between disc 34 and plate 36.

Now, when the reel .I'I functions as a supply electrically interlocked. The motor shaft 49 has pinned to it by a pin 50, a flange 52 in which are located gears 53 rotatable on shafts 54, the shafts being threaded into nuts 55 within the rim of a flange 56 mounted on the shaft 48 coaxially with shaft 49 and rotatable on bearings 49. The nuts 55 are not rotatable, but may be bodily moved or revolved within the rim of the flange 56. By turning shafts 54 with handles 60, the gears 53 may be locked in position so that they will not rotate. The gears 53 are in mesh with a ring gear 58 mounted on a collar 52" of flange 56 so that, when the gears 53 are locked, the flange 52 will drive flange 56. However, when the gears are free to rotate, the angular position of flange 52 may be adjusted with respect to flange 56.

. Thus, if there is a certain out-of-phase condireel, it is rotated by the pull of the film, slowly when the reel is full, and more rapidly as the film is reeled oil. At the same time, the shaft I8 and disc 3| are rotated in an opposite direction but in the same direction as the shaft 38. Since the disc 3| always rotates faster than disc 34, the pawls 32 slide over the disc and it is thus necessary to provide a drag on the reel IT to prevent the film from piling up. To provide such a drag, pawls 40, fixed to the casing, look a disc 4I mounted on bearing 4|, disc 4| being normally rotatable in the opposite direction through a frictional connection with shaft plate 36 through disc 34. This drag can be varied by adjusting the position of a thumb screw 42 which bears against a compression spring 43. The reel I9 is, of course, provided with a similar reversing mechanism within the casing 28 and has a similar adjusting screw 45. There is also provided a manual adjustment for the reel, such as a knurled screw 46 which is connected to a shaft geared with the shaft of the reel I9.

It is well known that, in order to photograph a projected motion picture on a translucent screen, the picture must be on the screen when the shutter of the camera is opened. It thus becomes necessary to synchronize the respective shutters of the projector and camera. This may be accomplished in the present mechanism by the assembly I3 shown in detail in Fig. 3 wherein the motor I I drives the projector through a type of fixed differential gears which may be adjusted after the camera and projector motor have been tion existing between the shutters of projector 5 and the camera 8 when the respective motors are electrically interlocked, they may be brought into exact synchronism by this adjustment.

Referring again to Fig. 2, the reversing motor I5, mentioned above, comprises a stator 62 and a rotor 63, the latter being mounted on a quill 64 adapted to rotate on bearings 65 interposed between the quill and a shaft 65, the shaft 66 being connected directly to the projector mechanism. The rotor 63 may be connected to the shaft 66 through the clutch mechanism I4 shown in detail in Fig. 3 and which will now be described. This clutch mechanism is an assembly comprising an H-shaped casting 69 slidable axially on the splined larger diameter portion ID of shaft 66 between a cupshaped flange II driven by motor I5 and a similar flange I2 driven by motor I I. Mounted within the casting 69 are diametrically opposing clutch pins 13 and I4, pin I3 being urged outwardly by a compression spring 15., and pin I4 being urged outwardly in the opposite direction by a compression spring I6. The pin I3 is adapted to be inserted in an aperture I3 in the flange I2 when the casting 69 is in the right-hand position, thereby connecting the shaft -48 driven by motor II to the projector shaft 66,

. while the pin I4 is adapted to be inserted in an aperture I4 in the flange II when the casting 69 is in the left-hand position, thereby connecting quill 64 driven by motor I5 to the projector shaft 66. Thus, the clutch may connect the projector to either motor I I or motor I5, the compression springs I5 and I6 causing the respective pins I3 and I4 to be inserted in respective apertures in case the pins and apertures do not coincide when the clutch is shifted. It is to be noted that a single pin is employed for making the connection between the projector shaft 66 and the respective motors. Now, since the drive is a direct oneto-one ratio, the use of a single pin will maintain synchronism between the camera and projector shutter regardless of the fact that the motor II may be periodically connected and disconnected from the projector.

The clutch I4 is operated by the lower end extension I8 of a magnetically operated lever arm I8 pivoted at IS, the end of the extension being set in the smaller diameter portion of the casting 69, as shown in Fig. 5, this view also showing the spring apertures and 80'. The splined interconnection between the shaft III and the casting 69 is shown at 8| The pivoted lever arm I8 is actuated in opposite directions by magnetic coils 84 and 85, the coil 54 shifting the casting 65 to the left to make connection with the motor I5, and the coil 85 shifting the casting to the right, as shown in accommodating rollers Fig. 3, to make connection with motor II. m-

though the lower portion 18' of the clutch-actor ating mechanism is a single element, the remainder of the lever comprises two branches, the top portions of which have shoes Figs. 4 and 9). Mounted between the arms is a magnetic element 89 which is attractedby the magnetic fields of coils 84 and 85 for actuating the lever 18. It is to be noted that, the segments 88 and 81 havenotches contacts 98 and 91, respectively. Thus, the posi-- tion of clutch I4 is determined by that coil (84 or 85) which was last energized. A condenser 98 is connected across the contacts to reduce burn ing thereof. I i

The control of the clutch I4 as well as the energization of motor II is controlled by a single element in the form of a lever I having a handle IOI' (see Figs. 6, 7, 8 and 9). This mechanism is in the form of an electrical control box mounted within a housing I04. The lever I00 is mounted for rotation in two directions by being pivoted at a point casting I08 which rotates on stub shafts I01 and I08. Mounted in an aperture of the casting I08 is a'switch 0' having a lever IIO which is adapted to makean'd break a circuit between two contact points III and H2 within the switch I10, depending upon the position of the handle I,0I (see Fig. 9). The switch lever IIO may be adjusted by two set screws I I3 and I I3.

The lever I00 has mounted thereon a double set of brush contacts H4, H5, H8 and Ill, each being urged outwardly by respective compression springs H4 and 8'. Contacts II4 and H5 are electrically interconnected by spring 4', as are contacts H8 and Ill by spring IIB. Contact elements on one side of lever I00, such as H5 and .I I8, are adapted to contact and slide along metallic segments I20 and I2I, while contact H4 is adapted to contact a fixed series of point contacts I22 and I23, while contact H1 is adapted to slide along either one of segments I31 and HI (see Fig. 6). There is a T-slot I00 in the top portion of housing I04 to permit the lever I00 to be moved in the two directions. The handle IOI moves the contactor elements mounted in lever I00 into a position intermediate the segments I20 and I2I and the contacts I22 and I23, after which the lever may be rotated on its axis I05 in either direction, and speed of film travel desired. A diagrammatic arrangement of this controlling switch and circuit is shown in Fig. 9, which will now be referred to for a description of the operation of the system.

As mentioned above, the motor II 'is the driving motor which is to operate in synchronism with the motor of camera iore, may be energized and controlled at a point remote from the projector, su h as at the camera. The other motor I5, however, is adaptedto advance the film in either direction through the projector. a This is accomplished by the control box manipulated by the handle IOI. Let us assume that projection has ceased and it is desired to return the film toa certain point. The projector operator first raises the lever IOI'in T- slot I00 from the position shown in the dotted lines I20 in' Fig. '1 to the position shown in the full lines 120" in this figure. By this operation, the switch lever H0 is operated so contact, is made with point III, as shown diagrammatically in Fig. .9. With the making of this contact, a

88 and 81 (see 90 and 9I cut therein for 94 and 95 which control I05 and being mounted in a depending upon the direction 8. Motor II, there-.

circuit is completed from a battery I25, or other suitable source of energy, over conductor 128,, through switch 0', through contact 98 (which is closed because the roller 94 is out of the notch 90), over conductor I21, through coil 84 and over conductor I28, back to the battery I25. This energization of the coil 84 pulls the armature, 89 to the right, thus shifting the clutch to the left, disconnecting motor II and connecting motor I5 to the projector, as above-described. When the armature 89 moves to the right, the roller 94 drops into the notch 90,- thus breaking the contacts at 98 and deenergizing the coil 84. At the same time, of course, the roller 35 is raised out of the notch 9I, making contacts 91, so that when the switch lever H0 is operated to contact point II2, a' circuit is completed from the battery I25, over conductors I30 and I3I and through coil-85 so theclutch will again connect motor I I to the projector.

Now with thehandle I I0 in the position shown in Fig. 9, it may be moved in either direction in the T-slot IIO' aboutpivot I05. Movement of the lever to the left, as shown in Fig. 6 by the dotted lines, will energize motor I5 over a circuit"v from a battery I35, or similar energy source, over conductor I38, segment I31, through interconnected contacts H1 and M8 to segment I2I, over conductor I39, through motor I5 (upwardly), over conductor 40, through segment I20, through interconnected contacts H5 and H4, and then through those contacts I22 and resistances I43, depending upon the position of the lever I00, over conductor I44, and back to battery I35. Thus, the motor I5 will rotate in a definite direction since the current is passing from' conductor I39 to conductor I40 and the speed thereof will be determined by the position of handle conductor I40 ID] with respectto contacts I22.

The above action will reverse the normal rotation of the projector and rewind the film, thus returning it to its starting point at any speed within the limits of the apparatus. If the starting point is passed, then the handle IN is moved to the right, completing a circuit from battery I35, over conductor I38, segment I31, over conductor I45, contacts I23 and resistances I48, depending upon the position of the handle I'0I, interconnected contacts 4 and H5, segment I20, over conductor I40, through motor I5 (downwardly), over conductor I39, segment I2I, interconnected contacts H8 and over conductor I41, over conductor I44 and back to battery I35. Thus, with the handle IN to the right, the current through the motor I5 is from to I39, thus reversing the first and advancing in this direction, of course, will depend upon the number of resistances I48 which are in the circuit with the motor. The handle may thus'be shifted from right to left until the proper starting frame of the film is found. Now, when the handle IOI direction of rotation of the motor is brought back to its central position and then dropped down in the II1, segment I4I,"

to rewind or advance the film in the projector.

We claim:

1. In combination, motion picture film feed mechanism, driving means for rotating said mechanism in a certain direction, independent driving means for rotating said mechanism in said certain direction and in a reverse direction, means for simultaneously disconnecting one of said driving means from said mechanism when the other of said driving means is connected thereto, said means reconnecting each of said disconnected driving means in the same angular relationship as existed during said first connection, and means for controlling the direction of rotation of said independent driving means and the speed of rotation thereof in any selected direction.

2. In combination, a motion picture film feed mechanism, a driving motor for rotating said mechanism in a certain direction, a second driving motor for rotating said mechanism in said certain direction and in a reverse direction, means for simultaneously disconnecting one of said driving motors from said mechanism when the other of said driving motors is connected thereto, said means reconnecting each of said disconnected driving motors in the same angular relationship as existed during said first connection and a direction and speed control means for said second motor.

3. A combination in accordance with claim 2 in which said disconnecting and connecting means includes a magnetic switch for controlling the connection and disconnection of each 01' said motors from said feed mechanism.

4. A motion picture projector comprising film advancing mechanism, said mechanism also adapted to advance said film in either direction through said projector, a synchronous driving motor for advancing said film at a substantially constant speed in a certain direction, a second driving means for said film mechanism adapted to advance said film in said certain direction when rotated in one direction, and to'reverse the travel of said film when rotated in another direction, a clutch intermediate said synchronous motor and said second driving means adapted to simultaneously connect one and disconnect the other of said motors alternately to said film mechanism, the connection between said mechanism and a respective motor always having the same angular position with respect to each other, and a controller for controlling the direction or rotation and the speed of rotation of said second driving means.

5. A motion picture projector in accordance with claim 4, in which said controller includes a magnetic switch adapted to operate said clutch.

6. A motion picture projector comprising a film advancing mechanism, a drive shaft therefor, a substantially constant speed motor for driving said mechanism, means for obtaining a predetermined angular relationship between the shaft of said driving motor and said drive shaft, a clutch for disconnecting the shaft of said motor from said drive shaft, said clutch reconnecting said shafts in their predetermined angular relationship, a second driving motor for said mechanism, said clutch connecting and disconnecting said second motor from said drive shaft, electrical means for operating said clutch, said electrical means comprising individually actuated energizing circuits, and means adapted to automatically break the last actuated circuit upon actuation of said clutch. r '7. A motion picture projector comprising a film advancing mechanism, film reels for said mechanism, a mechanism for operating said reels alternately as supply and takeup reels in accordance with the direction of rotation of said film mechanism, a drive shaft for said mechanism and said film reels, a substantially constant speed motor for said mechanism, a variable speed motor for said mechanism, a clutch intermediate said motorsfor simultaneously connecting one of said motors while disconnecting the other of said motors, said clutch always connecting a respective motor in the same angular position with respect to said mechanism, and a control box for controlling the connection of said motors to said drive shaft and for changing the speed and direction of rotation of said variable speed motor.

8. A motion picture projector comprising an intermittent film advancing mechanism, a substantially constant speed motor for driving said mechanism, a variable speed motor for driving said mechanism, means for alternately connecting one and disconnecting the other of said motors to said film mechanism, said connected motor being always connected in the same angular relationship with respect to said mechanism and a control box for said variable speed motor, said control box comprising a manually operative handle adapted to first actuate said connecting means for said motors and then change the speed and direction of rotation of said variable speed motor in accordance with the position of said handle.

9. A motion picture projection apparatus comprising a film feed mechanism, a substantially constant speed motor for driving said film feed mechanism, a variable speed motor for driving said film feed mechanism, said variable speed motor being adapted to advance said film forward and backward through said projector at diflerent speeds, and a manually operative controller for said variable speed motor, said controller comprising a manually operative handle movable in directions normal to one another, one direction of movement controlling the simultaneous connection of one and disconnection of the other of said motors from said film feed mechanism, and another direction of movement of said handle being adapted to vary the speed and direction of rotation of said variable speed motor.

10. A controlling system for a motion picture film projector comprising a plurality of driving motors for said projector, one of said motors adapted to drive said projector at a substantially constant speed in a certain direction, and another or said driving motors'being adapted to drive said projector at difierent speeds and in two directions, a drive shaft for said projector. means for connecting each of said motors at mutually exclusive intervals to said drive shaft,

one of said motors being disconnected simultaneously with the connection of the other of said motors, and means for remotely controlling said connecting means, said last-mentioned means also controlling the direction and speed of rotation of said projector.

11. A controlling system for a motion picture film projector comprising a plurality of driving motors for said projector, one of said motors.

adapted to drive said projector at a substananother of said driving motors being adapted for simultaneously connecting one of said motors I at mutually exclusive intervals to said drive shaft, means for remotely controlling said connecting means, said last-mentioned means also controlling the direction and speed of rotation of said projector, and said connecting means including a magnetic clutch individual energizing circuits therefor, and means adapted upon actuation of said clutch to automatically deenergize the circuit last energized.

12. A motion picture projector comprising a film advancing mechanism, a substantially constant speed motor for driving said mechanism, a second motor for driving said mechanism, a clutch for simultaneously connecting one of said motors whil disconnecting the other of said motors from said mechanism and vice versa, means for remotely controlling the actuation of said clutch, said means controlling the direction and speed of rotation of said second motor, and means included in said clutch for connecting each of said motors in the same angular relationship .with said mechanism.

13. A motion picture projector comprising a film advancing mechanism, a substantially constant speed motor for driving said mechanism, a second motor for driving said mechanism.

a clutch while disconnecting the other of said motors fromsaid mechanism and vice versa, and means included in said clutch for connecting each of said motors in the same angular relationship with said mechanism means including a movable element coaxially and intermediately arranged with the drive shafts of said motors and adapted to be magnetically shifted between said shafts.

14. A motion pictur projector comprising a film advancing mechanism, a substantially constant speed motor-tor driving said mechanism, a second motor for driving said mechanism, a clutch adapted to simultaneously connect one of said motors to said mechanism while disconnecting the other of said motors from said mechanism and vice versa, means for magnetically shifting said clutch, and a remote control circuit for actuating said magnetic means, said circuit including means for de-energizing said actuating circuit after it has functioned to shiit said clutch.

HARRY G. CUNNINGHAM. JOHN M. WIILSON,

, said last-mentioned 

